diff --git a/changelog.d/10983.misc b/changelog.d/10983.misc
new file mode 100644
index 0000000000..235899d14f
--- /dev/null
+++ b/changelog.d/10983.misc
@@ -0,0 +1 @@
+Log stack traces when a missing opentracing span is detected.
diff --git a/synapse/logging/opentracing.py b/synapse/logging/opentracing.py
index 03d2dd94f6..5276c4bfcc 100644
--- a/synapse/logging/opentracing.py
+++ b/synapse/logging/opentracing.py
@@ -339,6 +339,7 @@ def ensure_active_span(message, ret=None):
                     "There was no active span when trying to %s."
                     " Did you forget to start one or did a context slip?",
                     message,
+                    stack_info=True,
                 )
 
                 return ret